Philadelphia Weather in September: Climate, Temperature & Travel Tips
Avg 21.2°C · 112mm rain — September is autumn in Philadelphia.
- Avg high
- 26.0 °C
- Avg low
- 16.5 °C
- Avg
- 21.2 °C
- Precipitation
- 112 mm
Source: Open-Meteo Archive 2014–2023 · 10-year climate normals
Climate Overview
September in Philadelphia, United States brings autumn conditions: average temperature 21.2°C, average high 26.0°C, average low 16.5°C. Monthly rainfall averages 112mm, making it a moderate-rainfall time of year.
Conditions are pleasant for most travel activities.
What to Pack
- Short sleeves and light pants; sunglasses
- Light shoes or sandals
- A light rain jacket as backup
Best Things to Do
- Walking tours and city exploration
- Parks and outdoor cafes
- Seasonal food and night markets (where applicable)
Pros and Cons of Visiting in September
Pros:
- Pleasant temperatures for walking and outdoor sightseeing
- Shoulder season often means smaller crowds and lower prices
Cons:
- No major weather drawbacks for typical activities
Climate source: Open-Meteo Archive (2014–2023).
Colour = avg temperature · blue = cool · orange = warm
- 1 July 26.1°C
- 2 August 25.1°C
- 3 June 23.2°C
- 1 January 1.1°C
- 2 February 2.3°C
- 3 December 3.8°C
FAQ
01 What is the average temperature in Philadelphia in September? +
The average is 21.2°C, with a high of 26°C and a low of 17°C.
02 What is Philadelphia like to visit in September? +
It is autumn in Philadelphia, which is ideal for outdoor exploration.
03 Does it rain often in Philadelphia during September? +
Average rainfall is 112mm, which is moderate.
04 What should I pack for Philadelphia in September? +
Short sleeves and light pants; sunglasses; Light shoes or sandals.
05 Is September a peak travel season for Philadelphia? +
It is closer to off-season, with more reasonable prices and fewer crowds.
06 Where does this climate data come from? +
Monthly averages computed from Open-Meteo Archive 2014–2023 daily observations.
- Sources
- Open-Meteo Archive 2014-2023
- Updated
- 2026-04-17